1. Field of the Invention
The present invention relates to an electrodeless lighting system, and more particularly, to an electrodeless lighting system capable of selectively illuminating an electrodeless bulb among a plurality of electrodeless bulbs installed inside the resonator.
2. Description of the Background Art
In general, a lighting instrument using a microwave is an apparatus in which a microwave is added to an electrodeless plasma bulb thereby emitting visible rays and ultraviolet rays. The lighting instrument has a bulb with longer lifetimes than a general incandescent lamp, or a fluorescent lamp, and has excellent efficiency in lighting.
FIG. 1 is a sectional view illustrating a conventional electrodeless lighting system, and FIG. 2 is an enlarged sectional view illustrating a bulb of an electrodeless bulb assembly of FIG. 1.
As shown in FIG. 1, a conventional electrodeless lighting system includes a casing 1; a high-tension generator 2 mounted inside the casing 1, and for generating a high tension; a microwave generator 3 mounted inside the casing 1 at a certain interval between itself and the high-tension generator 2, and for generating a microwave; a waveguide 4 for guiding a microwave generated at the microwave generator 3; a resonator 5 installed at the outside of the casing 1 so as to communicate with the waveguide 4, and generating a high intensity electromagnet field by exciting the microwave guided thereto through the waveguide 4; an electrodeless bulb assembly 6 rotatably mounted inside the resonator 5, and including a bulb in which a luminescent material forms a plasma thereby generating light; a mirror 7 positioned at a lower surface of the electrodeless bulb assembly 6, and for upwardly reflecting the light emitted from the electrodeless bulb assembly 6; and a reflector 8 for concentrating light generated at the electrodeless bulb assembly 6, and upwardly reflecting the light.
Inside the casing 1, a first driving motor 9 for rotating the electrodeless bulb assembly 6 is installed, and a rotation shaft 9a of the first driving motor 9 is connected with a shaft portion 6a of the electrodeless bulb assembly 6 by a connecting shaft 9b. And also, inside the casing 1, a cooling fan 11 and a second driving motor 12 for driving the cooling fan 11 are mounted in order to cool the heat generated at the high tension generator 2 and the microwave generator 3. At the casing 11, an air duct 13 for guiding external air to the high-tension generator 2 and the microwave generator 3 is provided.
As shown in FIG. 2, the electrodeless bulb assembly 6 consists of a transparent bulb 6b filled with a luminescent material, and a shaft portion 6a extended from the bulb 6b so as to be connected with the connecting shaft 9b. 
Operations of the conventional electrodeless lighting system constructed as above will now be described.
When power is applied to an electrodeless lighting system, a high tension is generated at the high-tension generator 2, and a microwave is generated at a microwave generator by the high tension generated from the high-tension generator 2. The microwave is transmitted to a resonator 5 through a waveguide 4 and distributes a high intensity electromagnetic field at the resonator. At this time, the luminescent material within the electrodeless bulb 6b is discharged by the electromagnetic field, and simultaneously gasified, generating a plasma. The light which is emitted when the plasma is generated at the electrodeless bulb 6b is upwardly reflected by the mirror 7 and the reflector 8.
However, in the conventional lighting system, the electrodeless bulb assembly has only one bulb, so only one beam is emitted.